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Astrophysics

Title:
Spitzer Planet Limits around the Pulsating White Dwarf GD66

Abstract: We present infrared observations in search of a planet around the white
dwarf, GD66. Time-series photometry of GD66 shows a variation in the arrival
time of stellar pulsations consistent with the presence of a planet with mass >
2.4Mj. Any such planet is too close to the star to be resolved, but the
planet's light can be directly detected as an excess flux at 4.5um. We observed
GD66 with the two shorter wavelength channels of IRAC on Spitzer but did not
find strong evidence of a companion, placing an upper limit of 5--7Mj on the
mass of the companion, assuming an age of 1.2--1.7Gyr.